Purpose: The aim of this study was to determine residual heat deposition in hard dental tissues during ablation with Erbium lasers. Materials and Methods: Residual heat deposition was obtained from measured irradiated hard tissue temperature decay characteristics immediately following Erbium laser pulses. A comparison of the heating effects of the two most commonly used Erbium lasers in laser dentistry, namely Er:YAG and Er,Cr:YSGG, was made. Results: The measured residual heat was larger in enamel than in dentin for both laser sources. The amount of the unwanted residual heat that remains deposited in the tooth is for the H mode Er,Cr:YSGG laser twice as great, and for the S mode Er,Cr:YSGG laser more than 3 times as great as the deposited heat with the MSP mode Er:YAG laser. Conclusion: For Er,Cr:YSGG lasers, a larger share of the total absorbed laser energy remained in the tooth in the form of heat. This explains, at least partially, the observed lower ablation efficacy of Er,Cr:YSGG lasers compared to Er:YAG lasers.
Keywords: Er:YAG, Er,Cr:YSGG, erbium laser, heat deposition, dental laser, hard dental tissues